Retort and furnace



July 1 1924. 1,499,850

L, H. BONNARD RETORT AND FURNACE Filed Dec. 1, 1922 2- Sheets-Sheet 1HII 15' I v (\HQI MM 1W 77 k 9 50 v B] W WM. 97 m; W

July 1 1924. I 1,499,850

L. H. BONNA'RD HETORT AND FURNACE Filed Dec. 1, 1922 2 Sheets-Sheet. 3

INVENTOI.

Patented July l, 1924.

LEONARD HUGH BONNARD, OF LONDON, ENGLAND.

v nn'rozar Ann FURNACE. Y I

Application filed December 1, 192a Serial in. 604, 33.

To all whom g't may concern:

Be it known that I, LEONARD NARI), a subject of the King of England, residing at London, in England, have invented certain new and usefulImprovements inRetorts and Furnaces, of which the following is aspecification.

This invention consists of improvements in or relating to retorts andfurnaces.

Tlle primary object is to provide a mufiie furnace or retort in whichcarbonaceous ma include vegetable materials, crushed ores, V

and so forth, and are hereinafter referred to as mobile material. Underthe term furnace as used in the following specification and claims thereare to be understood to be included retorts, and generally any form ofthe apparatus, whether it be'heated externally or by the passage of hotgases through the interior or otherwise.

Various types of furnaces are known in which there is a vertical seriesof horizontal trays to support the mobile material, and in which rakesor blades (which may radiate from a central rotatable shaft) serve tokeep the mobile material turned over or agitated and also serve totransfer the material from tray to tray. One well-known example of suchapparatus is the Wedge niechanical furnace. I make no claim to theseknown arrangements.

Where the mobile material is to be subjected to heat treatment on aseries of trays, it is desirable in the first place that the mobilematerial fed to the apparatus should be distributed in substantiallyuniform layers (which may be thin layers) on the surfaces of the trays.It is also desirable that the material be turned over from time to .timeto expose fresh portionsto the surfaces of the trays, and that thematerial should be bodily moved over the surfaces of The object of thisinvention'is to.

cal retort or furnace there is provided the HUGH Boncombination of aseries of superposed. horizontaltrays having transfer openings forpassages ofmobile material from tray to tray, blades overlying thetrays, means for moving the blades over thejsurfaces of the. trays andmeans for raising and lowering the blades inrelation to thetraysso thatthey act alternately to spread the material over thetray surfaces and totransfer it toward and through the transfer openings:

- More specifically this invention comprises n a mechanical furnacethecom'bination of a series of superposed horizontal trays havingtransfer-openings for passage of mobile material from tray totray, avertical rota table shaft extending through the trays,

blades carried upon the shaft so as to overlie the trays and means for.raising and lowering the shaft with its vblades in relation to the traysso that the blades alternately spread the material overlthe traysurfaces and transfer it toward and through the transfer openings.

In the accompanying drawings whichillustrate diagrammatically I one formI of muf fie retort embodying thisinvention and spe cially suitable forthe carbonization of sawdust and for the heat treatment ofdeco-lourizingjcarbons- I T v V j Figure 1 isa central vertical sectionshowing the general arrangement of the appara f' Q Figure 2 is avertical section partly in ele- ,vation illustrating the retort proper;7

Figures 3, 4, 5, and 6 are diagrams illustrating the positions ofthedischarge holes in the hopper, the'top feed plate, the uppermost tray,and the second tray, respectively;

Figure 7 is a horizontal section on] the line 7 of Figure 2.

Referring first to thevertical cylindrical retortf2 by an annular space3 into which,projectftangen f tiallya "serieseofgas or liquid-fuelburners 41;. disposed near the bottom' of the appara tus. The retort E2discharges through an outlet 5 into a conveyor chamber 6 provided with agas outlet 7 "from which the products Figure-1, anjouter an- I nularbrickwork setting 1 s separated from otdistillation are led toalcondenser and to a conduit for the residualgaswhich may be for aportion of its-length by a water. tank 9. The treated and cooledmaterial is discharged from the chamber 6 through a vertical outlet 10and an expansion pipe 11 into a receiver 12 which is normally keptsealed against the access of air and can be readily replaced whenfilled.

The retort roper comprises an outer cylindrical casing 18 around whichthe heating medium or flame passes. WVithin this casing is a verticalseries of fixed horizontal trays 14 which derive their heat from thecasing and transfer the heat to the sawdust which is distributed overthe surfaces of the trays. Transfer openings in the form of slots 15 areprovided in the trays for the transfer of the sawdust gradually throughthe apparatus. The slots may be sectorshaped and the slot in each traymay be so arranged in relation to the slot in the tray next above itthat the sawdust has to travel almost completely round the tray beforeits discharge therefrom. A central vertical rotatable shaft 16 passesthrough the axes of the trays 14 and carries radial blades 17 as shownin Figure 7 there may be five radial blades for each tray. The shaft 16is free to move slightly in a vertical direction, and may be supportedon a transverse bar 18 carrying at its ends two rollers 19 engaging anupwardly-facing co-axial fixed cam surface 20 which determines theperiodic vertical movement of the shaft. It will be obvious that variousalternative methods may be employed for imparting the vertical movementto the shaft. In the form shown a spur wheel 21 with long teeth issecured to the shaft and engages with a corresponding spur wheel 22secured to a countershaft 23, having a driving pulley 24. To preventundue load on the cam, the shaft and the attached members may becounterbalanced to a considerable extent, say by a pivoted lever 25 andan adjustable weight 26. The object of the vertical movement of theshaft is to enable the radial blades 17 to be moved when required intocontact with th surfaces of the trays, and to be raised when required toa certain small distance from the trays, so as to spread the sawdust inthin layers over the surfaces of the trays. For example, in the casewhere the cam or the like allows the blades to be in contact with thetrays during a rotation of about I 36, and then raises the blades duringa rotation of about 144, the operation is as follows From a suitablefeed hopper 27, having an out-let 28 through the cover of the retort,the sawdust falls on to a feed plate 29, having a slot 30 therein. Aradial feed-arm 31 secured to the shaft 16 sweeps a certain regulatedquantity of sawdust away from under the hopper outlet 28 through theslot 30 on to the topmost of the trays 14.

Figures 3, 4, 5 and 6 indicate the relative intes ate positions of theslots 28, 30 and 15, the radial arms or blades being assumed to rotateclockwise when looking down upon them, so that as soon as the sawdust isswept away from the hopper hole 28 it passes almost at once through theslot 30 in the feed plate, but on each of the trays 14 the saw dust hasto be assed almost completely round the tray before it is dischargedtherefrom. During a rotation of the shaftthrough 144 the heap on thetopmost tray is spread out on the surface of the tray. The blades 17 arethen lowered into contact with the tray, and these blades, in movingthrough an angle of 36 in contact with the tray, effect a certainforward movement of the sawdust over the surface, and also turn over thematerial to a certain extent. The blades 17 are then again raised andeffect the spreading during a. further 144 rota tion. By this alternatespreading and shifting the material is gradually transferred through thefurnace and it will be noted that in using live radial blades which arein contact with the tray twice for 36 in each revolution, the wholesurface of each tray is swept over by the blades at each revolution.

Roughly speaking, the finer the material treated the thinner should bethe layers when spread out. Working with sawdust of 32 mesh to thelinear inch, quarter-inch layers can conveniently be used.

Apparatus for feeding the mobile material to the retort or furnace maytake various forms, it being only necessary that a periodic discharge ofthe mobile material on to the topmost tray should take place at asuitable place and at appropriate times.

The blades may take a variety of forms, and may, if desired, bespecially cooled, e. g. water-cooled.

The method of heating the mobile mate rial may be modified in variousways, for example, in the case of the roasting of ores, the hot gasesmay actually pass up through the retort itself and be brought in contactwith the mobile material.

It is desirable, on the one hand, not to leave portions of the traysurfaces bare or unoccupied for any considerable period, and, on theother hand, not to leave por tions of the tray surfaces which are neverswept over by the blades whilst in contact therewith.

The number of radial blades employed and the timing of their verticalmovements can be readily selected to effect both these objects.

To this end it is useful to point out that where the blades are loweredinto contact with the tray at uniform intervals more than once in arevolution, the period of contact necessary depends both on the numberof blades and on the number of times of contact, and is inversely as theleast common multiple of thesetwo factors. Thus for a given period ofcontact the maximum sweeping of the surface with the minimum number ofblades is obtained if the number of the blades and the number of timesof contact are incommensurable (prime to For example, where the What Iclaim as my invention and-desire to secure by Letters Patent is:

1. V In a mechanlcal furnace the combination of a series of superposedhorizontal trays having transfer openings for passage of mobile materialfrom tray to tray, blades overlying the trays, means for moving theblades over the surfaces of the trays to feed forward the material andmeans for raising and lowering the blades in relation to the trays sothat they act alternately while moving in the direction to feed forwardthe material to spread the latter over the tray surfaces and to transferit toward and through the transfer openings.

2. In a mechanical furnace the comb-ination of a series of superposedhorizontal trays having transfer openings for passage of mobile materialfrom tray to tray, a vertical rotatable shaft extending through thetrays, blades carried upon the shaft so as to overlie the trays andmeans for raising and lowering the shaft with its blades in relation tothe trays so that the blades while moving in the direction to feedforward the material alternately spread the latter over the traysurfaces and transfer it toward and through the transfer openings.

3. In a mechanical furnace the combina tion of a series of superposedhorizontal trays having transfer openings for passage of mobile materialfrom tray to tray, a vertical rotatable shaft extending through thetrays, blades carried upon the shaft so 'as to overlie the trays and acam and roller device mounted as to one element upon the shaft and as tothe other element on a fixed part of the furnace so as, during rotationof the shaft in the direction to feed forward the material, alternatelyto raise the shaft with the blades in relation to the trays to spreadthe material and to lower it so that the blades contact with the traysurfaces and transfer the material toward and through the transferopenings.

4. In a mechanical furnace the combination of a series of superposedhorizontal trays having transfer openings for passage of mobile materialfrom tray to tray, a vertical rotatable shaft extending through thetrays, blades carried upon the shaft so as to overlie the trays, aroller mounted upon the shaft, and a fixed cam co-axial with the shaftbelow the roller so as, during rotation of the shaft in the direction tofeed forward the material, alternately to raise the shaft with theblades, in relation to the trays to spread the material and to lower itso that the blades contact with the tray surfaces and transfer thematerial toward and through the transfer openings' 5. In a mechanicalfurnace the combination of a series of superposed horizontal trayshavingtransfer openings for passage of mobile material from tray to tray, avertical rotatable shaft extending through the trays, blades carriedupon the shaft so as to overlie the trays, two rollers carried upon theshaft on opposed sides thereof and a fixed cam co-axial with the shaftbelow the rollers soas, during rotation of the shaft in the direction tofeed forward the material, alternately to raise the shaft with theblades in relation to the trays to spread the material and to lower itso that the blades contact with the tray surfaces and transfer thematerial toward and through the transfer openings.

3 6. In a mechanical furnace the comblnation of a series of superposedhorizontal of mobile material from trayto tray, a vertical rotatableshaft extending through the trays, means for raising and lowering theshaft in relation to the trays more than once in each revolution andblades carried upon the shaft so as to be lowered into contact with thetrays when the shaft is lowered, the number of blades for each traybeing incommensurable with the number of times of contact of the bladeswith the trays per revolution.

7. In a mechanical furnace the combination of a furnace casing having adelivery opening to the interior at the top, a feed plate within thecasing below the delivery opening, a series of superposedv horizontaltrays within the casing below the feed plate having transfer openingsfor passage of material from tray totray, a central vertical rotatableshaft extending through the trays to the outside of the casing, bladescarried upon the shaft so as to overlie the trays, a feed arm rotatedwith the shaft so as to pass between the delivery opening and the feedplate and to sweep a portion of material from below the delivery openingand off the feed plate on to the first tray, and means for raising andlowering the shaft with its blades in relation to the trays opening, aseries of superposed horizontal.

&

shaft outside the casing and a fixed cam coaxial with the shaft belowthe rollers so as, during rotation of the shaft in the direction to feedforward the material, alternately to raise the shaft with the blades inrelation to the trays to spread the material and to lower it so that theblades contact with the tray surfaces and transfer the ma terial towardand through the transfer openings.

In testimony whereof I affix my signature.

LEONARD HUGH BONNARD.

